CN112822469B - Automatic focusing projection method and system - Google Patents
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- H—ELECTRICITY
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- H04N9/00—Details of colour television systems
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- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
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- H—ELECTRICITY
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- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3141—Constructional details thereof
- H04N9/317—Convergence or focusing systems
Abstract
The embodiment of the invention relates to the technical field of digital projection display, in particular to an automatic focusing projection method and system. The embodiment of the invention provides an automatic focusing projection method, which is used for an automatic focusing projection system, wherein the automatic focusing projection system comprises a distance measurement unit, a projection unit and a reflection unit, and the automatic focusing projection method comprises the following steps: acquiring a depth image of the distance measuring unit, and obtaining a vertical projection distance from the distance measuring unit to a projection plane according to the depth image; obtaining the position information of the central point of the projection picture in the depth image according to the elevation angle of the reflection unit and the vertical projection distance; obtaining the projection distance between the projection unit and the projection picture according to the position information; and focusing the projection unit according to the projection distance. The method can realize real-time automatic focusing in the reflective dynamic projection system.
Description
Technical Field
The embodiment of the invention relates to the technical field of digital projection display, in particular to an automatic focusing projection method and system.
Background
In recent years, with the rapid development of semiconductor display technology, projection technology has rapidly developed, and a large number of projection apparatuses have appeared on the market. At present, various application scenes need to use dynamic projection technology, such as large-scale stages, security alarms, intelligent traffic and the like, and the specific requirements of different scenes are met through the movement of a projection picture in space. In a dynamic projection system, real-time auto-focusing is a very important issue. Since the projection position of the moving projection system will change continuously, the projection distance will also change continuously, and if the fixed focus scheme is adopted, the projection picture will appear blurred inevitably. Therefore, in a dynamic projection system, real-time autofocus technology is required.
Some solutions have been tried and applied in mobile projection systems, for example, by placing a TOF (time Of flight) component beside the projection light engine, which moves together with the TOF component. Since the projection image is always located at the center of the detection area of the TOF assembly, the central detection distance of the TOF assembly is the projection distance of the system. In the actual use process, the position of the focusing lens can be adjusted according to the projection distance, so that automatic focusing is realized.
However, in reflective-type dynamic projection (i.e. controlling the movement of the projection screen by the rotation of the mirror) systems, there is still no effective real-time auto-focusing solution.
Disclosure of Invention
In view of the foregoing defects in the prior art, embodiments of the present invention mainly solve the technical problem of providing an auto-focusing projection method and system, which can implement real-time auto-focusing in reflective dynamic projection.
In order to solve the above technical problem, one technical solution adopted by the embodiment of the present invention is: the method is used for an automatic focusing projection system, the automatic focusing projection system comprises a distance measuring unit, a projection unit and a reflection unit, the distance measuring unit is used for obtaining a depth image, the projection unit is used for projection, and the reflection unit is used for changing the emergent ray direction of the projection unit; the automatic focusing projection method comprises the following steps: acquiring a depth image of the distance measuring unit, and obtaining a vertical projection distance from the distance measuring unit to a projection plane according to the depth image; obtaining the position information of the central point of the projection picture in the depth image according to the elevation angle of the reflection unit and the vertical projection distance; obtaining the projection distance between the projection unit and the projection picture according to the position information; and focusing the projection unit according to the projection distance.
In some embodiments, the obtaining a depth image of the ranging unit and obtaining a vertical projection distance from the ranging unit to a projection plane according to the depth image includes: and acquiring a depth image of the distance measuring unit, and determining the depth corresponding to the center position of the depth image as the vertical projection distance.
In some embodiments, the obtaining, according to the elevation angle of the reflection unit and the vertical projection distance, position information of a center point of a projection picture in the depth image includes: and obtaining the position information according to the elevation angle, the vertical projection distance and a first corresponding table, wherein the first corresponding table represents the corresponding relation of the elevation angle, the vertical projection distance and the position information.
In some embodiments, the method further comprises: acquiring the corresponding relation of the elevation angle, the vertical projection distance and the position information represented by the first corresponding table; and establishing the first corresponding table based on the corresponding relation.
In some embodiments, the focusing of the projection unit according to the projection distance includes: obtaining the target position of the projection lens according to the projection distance; and controlling the focusing device to move the projection lens to the target position according to the target position.
In some embodiments, the obtaining the target position of the projection lens according to the projection distance includes: and obtaining the target position of the projection lens according to the projection distance and a second corresponding table, wherein the second corresponding table represents the corresponding relation between the projection distance and the position of the projection lens.
In order to solve the above technical problem, an embodiment of the present invention further provides an auto-focus projection system, where the auto-focus projection system includes: the device comprises a distance measuring unit, a projection unit, a reflection unit and a control unit, wherein the control unit is respectively connected with the distance measuring unit, the projection unit and the reflection unit; the distance measurement unit is used for acquiring a depth image; the projection unit is used for projecting, and comprises a focusing device and a projection lens which can move along an optical axis, wherein the focusing device is used for adjusting the position of the projection lens; the reflection unit is used for changing the emergent ray direction of the projection unit; the control device includes: at least one processor, and a memory communicatively coupled to the at least one processor, wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any of the first aspects.
In some embodiments, the reflection unit is a mirror having a minimum elevation angle and a maximum elevation angle, and the half field angle of the ranging unit should satisfy:
wherein θ is a half field angle of the ranging unit, βminIs the minimum elevation angle, beta, of the mirrormaxIs the maximum elevation angle of the mirror.
In some embodiments, the ranging unit is a 3D camera, a TOF sensor, and/or a structured light camera.
In order to solve the above technical problem, in a third aspect, an embodiment of the present invention further provides a non-volatile computer-readable storage medium storing computer-executable instructions that, when executed by a processor, cause the processor to perform the auto-focus projection method according to any one of the first aspect.
To solve the above technical problem, in a fourth aspect, the present invention further provides a computer program product including a computer program stored on a computer-readable storage medium, the computer program including program instructions that, when executed by a computer, cause the computer to execute the auto-focus projection method according to any one of the above first aspects.
The beneficial effects of the embodiment of the invention are as follows: different from the prior art, an embodiment of the present invention provides an auto-focus projection method for an auto-focus projection system, where the auto-focus projection system includes a distance measurement unit, a projection unit, and a reflection unit, and the auto-focus projection method includes: acquiring a depth image of the distance measuring unit, and obtaining a vertical projection distance from the distance measuring unit to a projection plane according to the depth image; obtaining the position information of the central point of the projection picture in the depth image according to the elevation angle of the reflection unit and the vertical projection distance; obtaining the projection distance between the projection unit and the projection picture according to the position information; and focusing the projection unit according to the projection distance. The method can realize real-time automatic focusing in the reflective dynamic projection system.
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One or more embodiments are illustrated by the accompanying figures in the drawings that correspond thereto and are not to be construed as limiting the embodiments, wherein elements/modules and steps having the same reference numerals are represented by like elements/modules and steps, unless otherwise specified, and the drawings are not to scale.
FIG. 1 is a block diagram of an auto-focus projection system according to an embodiment of the present invention;
fig. 2 is a schematic structural block diagram of a control unit according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of an optical path of an auto-focus projection system according to an embodiment of the present invention;
FIG. 4 is a flowchart illustrating an auto-focus projection method according to an embodiment of the present invention;
FIG. 5 is a schematic flow chart of step S1 in FIG. 4;
FIG. 6 is a schematic flow chart of step S2 in FIG. 4;
FIG. 7 is a schematic diagram of an exit light path of an auto-focus projection system according to an embodiment of the present invention;
fig. 8 is a flowchart of step S4 in fig. 4.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
In order to facilitate an understanding of the present application, the present application is described in more detail below with reference to the accompanying drawings and specific embodiments. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
It should be noted that, if not conflicted, the various features of the embodiments of the invention may be combined with each other within the scope of protection of the present application. In addition, although the functional blocks are divided in the device diagram, in some cases, the blocks may be divided differently from those in the device. Further, the terms "first," "second," and the like, as used herein, do not limit the data and the execution order, but merely distinguish the same items or similar items having substantially the same functions and actions.
Referring to fig. 1, fig. 1 is a schematic structural block diagram of an auto-focus projection system according to an embodiment of the present invention, and as shown in fig. 1, the auto-focus projection system 100 includes: the distance measuring device comprises a distance measuring unit 10, a projection unit 20, a reflection unit 30 and a control unit 40, wherein the control unit 40 is respectively connected with the distance measuring unit 10, the projection unit 20 and the reflection unit 30.
Wherein the ranging unit 10 is used for acquiring a depth image. In some of these embodiments, the ranging unit 10 is a 3D camera, a TOF sensor and/or a structured light camera. In other embodiments, the distance measuring unit 10 may also be a microwave radar, or any other suitable distance measuring device, which is not limited herein.
The reflection unit 30 is used for changing the direction of the emergent ray of the projection unit 20. Specifically, the reflection unit 30 is disposed opposite to the projection unit 20, and can adjust a relative angle with the projection unit 20, so as to adjust the direction of the outgoing light of the projection unit 20. In the embodiment of the present invention, the reflection unit 30 preferably adopts an optical device with high reflectivity to ensure the quality of the projection image, and the reflection unit 30 is a reflection device provided with a rotation mechanism, and the rotation mechanism preferably adopts a device with high measurement accuracy of the rotation angle to ensure that the rotation angle of the reflection unit 30 can be precisely adjusted.
The projection unit 20 is used for projection, and specifically, the projection content of the projection unit 20 includes an image, a video or a Unity animation. In some embodiments, the projection unit 20 includes a focusing device and a projection lens movable along an optical axis, the focusing device is connected to the control unit 40, and the focusing device is used for adjusting the position of the projection lens according to a signal of the control unit 40.
The control unit 40 is used for controlling the distance measuring unit 10, the projecting unit 20 and the reflecting unit 30 to work, and processing data to obtain a result. The control unit 40 includes: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the auto-focus projection method as described in any one of the following.
Referring to fig. 2, the control unit 40 includes at least one processor 41 and a memory 42 communicatively connected to the at least one processor 41, wherein one processor 41 is taken as an example in fig. 2.
The processor 41 and the memory 42 may be connected by a bus or other means, such as the bus connection in fig. 2.
The memory 42 may include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function; the storage data area may store data created from use of the autofocus projection system, and the like. Further, the memory 42 may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid state storage device. In some embodiments, memory 42 optionally includes memory located remotely from processor 41, which may be connected to the processor via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
In some embodiments, referring to the left diagram of fig. 3, the reflecting unit 30 is a mirror. The initial emergent light of the projection unit 20 of the automatic focusing projection system 100 is directed vertically upwards, the reflector 30 is disposed in the vertical direction, and it should be noted that the horizontal lines a, b, c are horizontal lines with the same height, the center of the distance measuring unit 10 is at the same height as the reflective center point of the reflector 30, and the distance between the center of the distance measuring unit 10 and the reflective center point is required to be as small as possible. The central point of the reflected light is also the central point of the reflected light of the projection unit 20 at the reflector 30, and the included angle between the distance measuring unit 10 and the reflector 30 in the vertical direction is β0The mirror 30 has a minimum elevation angle and a maximum elevation angle, and in order to satisfy that the distance measuring unit 10 can detect the position of the projection picture, the half-field angle of the distance measuring unit 10 should satisfy:
where θ is a half field angle of the ranging unit 10, βminIs the minimum elevation angle, beta, of the mirrormaxIs the maximum elevation angle of the mirror. The satisfied relationship is derived as follows:
first, referring to the left diagram of fig. 3 again, it should be noted that the horizontal lines a, b, c are horizontal lines with the same height, when the mirror reaches the maximum elevation angle βmaxWhen the initial emergent light of the projection unit 20 is reflected by the reflector 30, the reflected light is reflectedHas an elevation angle of
The elevation angle of the normal d direction of the distance measuring unit 10 is
Then, to enable the distance measuring unit 10 to detect the distance of the position of the projected image, the following condition should be satisfied:
βr+θ≥β
namely:
this makes it possible to obtain:
θ≥βmax-β0
referring to the right diagram of FIG. 3, when the mirror reaches the minimum elevation angle βminWhen the initial emergent light of the projection unit 20 is reflected by the reflector 30, the elevation angle of the reflected light is
The elevation angle of the normal direction d of the distance measuring unit 10 is
Then, to enable the distance measuring unit 10 to detect the distance of the position of the projected image, the following condition should be satisfied:
βr-θ≤β
namely:
this makes it possible to obtain:
θ≥β0-βmin
bound theta ≧ betamax-β0And theta.gtoreq.beta0-βminObtaining the installation angle and the minimum field angle of the distance measuring unit 10:
in practical applications, a range-finding unit 10 with a larger field of view can be used, i.e. one that has a higher field of view
To ensure sufficient coverage of the moving area of the projected picture. In practical application, the installation angle of the distance measuring unit 10 and the reflector 30 can be set according to practical requirements, and only the requirement that theta is more than or equal to beta is met simultaneouslymax-β0And theta.gtoreq.beta0-βminAnd (4) finishing.
The invention also provides an embodiment of the automatic focusing projection method, which is applied to the automatic focusing projection system. Referring to fig. 4, a flow chart of an auto-focus projection method according to an embodiment of the present invention is shown, where the method includes, but is not limited to, the following steps:
step S1: acquiring a depth image of the distance measuring unit, and obtaining a vertical projection distance from the distance measuring unit to a projection plane according to the depth image;
specifically, when the reflector rotates, the projection picture moves in space, and the distance measuring unit can measure the distance in each direction in real time and generate a depth image; the acquired depth image information should contain depth information of the projection plane so that a perpendicular projection distance of the ranging unit to the projection plane can be obtained. In some other embodiments, the depth image information further includes depth information of other objects in space.
Specifically, referring to fig. 5, the step S1 is:
step S11: and acquiring a depth image of the distance measuring unit, and determining the depth corresponding to the center position of the depth image as the vertical projection distance.
Since the distance measuring unit and the reflective center point of the reflection unit can be regarded as the same point, the distance corresponding to the center position of the depth image obtained by the distance measuring unit is close to the distance from the reflective center point of the reflection unit to the projection plane, and the vertical projection distance from the distance measuring unit to the projection plane is approximately regarded as the vertical projection distance from the reflective center point of the reflection unit to the projection plane.
Step S2: obtaining the position information of the central point of the projection picture in the depth image according to the elevation angle of the reflection unit and the vertical projection distance;
specifically, referring to fig. 6, the step S2 is:
step S21: and obtaining the position information according to the elevation angle, the vertical projection distance and a first corresponding table, wherein the first corresponding table represents the corresponding relation of the elevation angle, the vertical projection distance and the position information.
Referring to fig. 7, in the auto-focus projection system, since the distance measuring unit and the reflective center of the reflector are on the same horizontal plane, the distance measuring unit and the reflective center coincide at a point a when viewed from a direction perpendicular to the paper plane, and when the reflector has an elevation angle β, the elevation angle of the reflected light e of the projection unit is β
If the included angle between the distance measuring unit and the reflector is beta0The normal d elevation angle of the distance measuring unit is
It can be seen that, in the vertical direction, the reflected light e of the projection unit is not parallel to the normal d of the ranging unit, so the projection image is not located at the vertical center position of the depth image obtained by the ranging unit, and the position of the center point of the projection image in the depth image is related to the elevation angle of the reflector and the vertical projection distance from the reflective center point to the projection plane. Meanwhile, in the actual process of the auto-focus projection system, please refer to the right diagram of fig. 7, when looking down vertically, the installation position and reflection of the distance measuring unitThe reflecting central points of the units have certain distance in the horizontal direction, so that the projection picture at the projection position is not positioned at the horizontal center of the depth image obtained by the distance measuring unit, but has displacement in the horizontal direction, and the position of the central point of the projection picture in the depth image can be seen to change along with the change of the vertical projection distance from the reflecting central point to the projection plane.
Therefore, the corresponding relation of the elevation angle of the reflector, the vertical projection distance and the position of the central point of the projection picture in the depth image can be constructed firstly. Specifically, in some embodiments, the correspondence relationship between the elevation angle, the vertical projection distance, and the position information is characterized by first obtaining the first correspondence table: then, the first corresponding table is established based on the corresponding relation. For example, firstly, the coordinate (x, y) and the elevation angle β of the reflector of the projection image in the depth image obtained by the distance measuring unit and the vertical projection distance R from the reflection center point of the reflector to the projection plane are establishedpA first correspondence table therebetween, wherein βmin≤β≤βmax，Rpmin≤R≤Rpmax,1≤x≤m,1≤y≤n，βminIs the minimum elevation angle, beta, of the mirrormaxIs the maximum elevation angle, R, of the mirrorpminIs the minimum vertical projection distance, R, from the reflecting center point of the reflector to the projection planepmaxThe maximum vertical projection distance from the reflecting center point of the reflector to the projection plane is defined, and m and n are the width and height of the image obtained by the distance measuring unit respectively. Then, the first mapping table is a set of coordinates of the corresponding projection picture center point in the depth image under different mirror elevation angles and vertical projection distances from different mirror reflection center points to the projection plane. It should be noted that in the process of establishing the first correspondence table, the direction of the light reflected by the mirror should be made perpendicular to the projection plane, and the projection screen should be square. In the actual process of establishment, the operation can be performed by a control variable method, for example, the angle of the reflector can be fixed at a preset angle, then the corresponding relationship between the vertical projection distance and the coordinate is established, and in the actual process, the establishment process can be freely set, and the establishment process does not need to be limited by the embodiment of the inventionThe method of (1).
Since the vertical projection distance from the ranging unit to the projection plane is approximately regarded as the vertical projection distance from the reflective center point of the reflection unit to the projection plane in step S1, the distance corresponding to the center position of the depth image obtained by the ranging unit is regarded as the vertical projection distance from the reflective center point to the projection plane after obtaining the distance; and then, searching according to the elevation angle and the first corresponding table to obtain position information, namely obtaining the coordinates of the depth image of the central point of the projection picture at the distance measuring unit.
Step S3: obtaining the projection distance between the projection unit and the projection picture according to the position information;
specifically, when a position coordinate of the center of the projection picture in the depth image is obtained, depth information corresponding to the position coordinate is determined in the depth image, and then a preset fixed distance from the projection unit to a reflection central point of the reflection unit is added to a distance corresponding to the depth information to obtain a projection distance between the projection unit and the projection picture. In practical application, the preset fixed distance may be set according to actual needs, and is not limited herein.
Step S4: and focusing the projection unit according to the projection distance.
The focal length of a projection lens in the automatic focusing projection system can be adjusted between a minimum focal length and a maximum focal length, and meanwhile, the focal length of the lens and the projection distance have a one-to-one correspondence relationship in the focusing range of the projection lens, wherein the minimum focal length corresponds to the minimum projection distance, the maximum focal length corresponds to the maximum projection distance, and the minimum adjustable projection distance and the maximum adjustable projection distance determine the zooming range [ D ]0,D1]I.e. at the projection distance [ D ]0,D1]Within the range, the focusing device can be used for focusing the projection lens which can move along the optical axis, so that the projection picture is clearer.
Specifically, referring to fig. 8, the step S4 includes:
step S41: obtaining the target position of the projection lens according to the projection distance;
step S42: and controlling the focusing device to move the projection lens to the target position according to the target position.
Specifically, the target position of the projection lens is obtained according to the projection distance and a second correspondence table, wherein the second correspondence table represents the correspondence between the projection distance and the position of the projection lens.
In some embodiments, a second correspondence table of positions of the projection lenses and projection distances within the variable focal range of the projection lenses may be pre-established, where the second correspondence table is a set of corresponding lens positions at different projection distances within the variable focal range of the projection lenses. After the projection distance between the projection unit and the projection position is obtained, the target position of the projection lens corresponding to the projection distance is found through the second corresponding table, and then the projection lens is adjusted to the target position through the focusing device, so that automatic focusing is realized.
The automatic focusing projection method provided by the embodiment of the invention can realize automatic focusing in reflective dynamic projection in real time, and when the elevation angle of the reflection unit or the position of the projection plane changes, the projection picture can be kept clear when moving in space, so that the visual experience of a user is improved.
Embodiments of the present invention also provide a non-transitory computer storage medium storing computer-executable instructions, which are executed by one or more processors, such as one processor 41 in fig. 2, to enable the one or more processors to perform the autofocus projection method in any of the above method embodiments, such as performing the autofocus projection method in any of the above method embodiments, for example, performing the steps shown in fig. 4 to 8 described above; the functions of the various devices described in fig. 1 may also be implemented.
Embodiments of the present invention also provide a computer program product comprising a computer program stored on a non-volatile computer-readable storage medium, the computer program comprising program instructions that, when executed by a computer, cause the computer to perform an auto-focus projection method in any of the above-described method embodiments, for example, to perform the method steps of fig. 4 to 8 described above, to implement the functions of the apparatuses of fig. 1.
The embodiment of the invention provides an automatic focusing projection method, which is used for an automatic focusing projection system, wherein the automatic focusing projection system comprises a distance measurement unit, a projection unit and a reflection unit, and the automatic focusing projection method comprises the following steps: acquiring a depth image of the distance measuring unit, and obtaining a vertical projection distance from the distance measuring unit to a projection plane according to the depth image; obtaining the position information of the central point of the projection picture in the depth image according to the elevation angle of the reflection unit and the vertical projection distance; obtaining the projection distance between the projection unit and the projection picture according to the position information; and focusing the projection unit according to the projection distance. The method can realize automatic focusing in the reflective dynamic projection system.
It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a general hardware platform, and certainly can also be implemented by hardware. Based on such understanding, the above technical solutions substantially or otherwise contributing to the related art may be embodied in the form of a software product, which may be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes a plurality of instructions for executing the method according to each embodiment or some parts of the embodiments by at least one computer device (which may be a personal computer, a server, or a network device, etc.).
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. An automatic focusing projection method is characterized in that the method is used for an automatic focusing projection system, the automatic focusing projection system comprises a distance measuring unit, a projection unit and a reflection unit, the distance measuring unit is used for obtaining a depth image, the projection unit is used for projection, the reflection unit is used for changing the emergent ray direction of the projection unit, and the distance measuring unit and the reflection center point of the reflection unit are located at the same height; the automatic focusing projection method comprises the following steps:
acquiring a depth image of the distance measuring unit, and obtaining a vertical projection distance from the distance measuring unit to a projection plane according to the depth image;
obtaining the position information of the central point of the projection picture in the depth image according to the elevation angle of the reflection unit and the vertical projection distance;
obtaining the projection distance between the projection unit and the projection picture according to the position information;
and focusing the projection unit according to the projection distance.
2. The auto-focus projection method according to claim 1, wherein the obtaining a depth image of the distance measuring unit and obtaining a vertical projection distance from the distance measuring unit to a projection plane according to the depth image comprises:
and acquiring a depth image of the distance measuring unit, and determining the depth corresponding to the center position of the depth image as the vertical projection distance.
3. The autofocus projection method of claim 2, wherein obtaining the position information of the center point of the projection screen in the depth image according to the elevation angle of the reflection unit and the vertical projection distance comprises:
and obtaining the position information according to the elevation angle, the vertical projection distance and a first corresponding table, wherein the first corresponding table represents the corresponding relation of the elevation angle, the vertical projection distance and the position information.
4. The autofocus projection method of claim 3, further comprising:
acquiring the corresponding relation among the elevation angle, the vertical projection distance and the position information;
and establishing the first corresponding table based on the corresponding relation.
5. The auto-focus projection method according to claim 1, wherein the projection unit includes a focusing device and a projection lens movable along an optical axis, and the focusing of the projection unit according to the projection distance includes:
obtaining the target position of the projection lens according to the projection distance;
and controlling the focusing device to move the projection lens to the target position according to the target position.
6. The auto-focus projection method according to claim 5, wherein the obtaining the target position of the projection lens according to the projection distance comprises:
and obtaining the target position of the projection lens according to the projection distance and a second corresponding table, wherein the second corresponding table represents the corresponding relation between the projection distance and the position of the projection lens.
7. An autofocus projection system, comprising: the device comprises a distance measuring unit, a projection unit, a reflection unit and a control unit, wherein the control unit is respectively connected with the distance measuring unit, the projection unit and the reflection unit;
the distance measurement unit is used for acquiring a depth image;
the projection unit is used for projecting, and comprises a focusing device and a projection lens which can move along an optical axis, wherein the focusing device is used for adjusting the position of the projection lens;
the reflection unit is used for changing the emergent ray direction of the projection unit;
the control unit includes:
at least one processor, and
a memory communicatively coupled to the at least one processor, wherein,
the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-6.
8. The autofocus projection system of claim 7, wherein the reflective unit is a mirror having a minimum elevation angle and a maximum elevation angle, and wherein the half field angle of the ranging unit is such that:
wherein the content of the first and second substances,
for a half field angle of the ranging unit,
is the minimum elevation angle of the mirror,
is the maximum elevation angle of the mirror.
9. The autofocus projection system of claim 8, wherein the distance measurement unit is a 3D camera, a TOF sensor, and/or a structured light camera.
10. A non-transitory computer-readable storage medium storing computer-executable instructions for causing a computer to perform the auto-focus projection method according to any one of claims 1 to 6.
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| PCT/CN2021/082411 WO2022141825A1 (en) | 2020-12-31 | 2021-03-23 | Automatic focusing projection method and system |
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| CN114173063B (en) * | 2022-02-11 | 2022-05-20 | 杭州灵西机器人智能科技有限公司 | Focusing method of structure light camera based on variable-focus lens and structure light camera |
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| JPH068925B2 (en) * | 1988-12-26 | 1994-02-02 | 株式会社トプコン | Auto focus projector |
| JP4702072B2 (en) * | 2006-01-20 | 2011-06-15 | カシオ計算機株式会社 | Projection device, distance measurement elevation angle control method and program for projection device |
| US20170374331A1 (en) * | 2016-06-27 | 2017-12-28 | Intel Corporation | Auto keystone correction and auto focus adjustment |
| US11303859B2 (en) * | 2016-09-29 | 2022-04-12 | Stmicroelectronics (Research & Development) Limited | Time of flight sensing for brightness and autofocus control in image projection devices |
| CN106791739A (en) * | 2016-11-28 | 2017-05-31 | 北京小米移动软件有限公司 | Projecting apparatus and its focusing method and device |
| JP2020522002A (en) * | 2017-06-02 | 2020-07-27 | エスゼット ディージェイアイ テクノロジー カンパニー リミテッドＳｚ Ｄｊｉ Ｔｅｃｈｎｏｌｏｇｙ Ｃｏ．，Ｌｔｄ | Method and system for recognizing, tracking, and focusing a moving target |
| CN107589625B (en) * | 2017-09-30 | 2020-05-29 | 歌尔科技有限公司 | Automatic zooming method of projector and projector |
| CN108710251A (en) * | 2018-04-20 | 2018-10-26 | 广景视睿科技（深圳）有限公司 | A kind of Atomatic focusing method, device and projecting apparatus |
| JP6822445B2 (en) * | 2018-07-02 | 2021-01-27 | カシオ計算機株式会社 | Projector, projection method and program |
| CN110191328A (en) * | 2019-06-19 | 2019-08-30 | 广景视睿科技（深圳）有限公司 | A kind of trend projection arrangement, method and projector |
| CN110462438A (en) * | 2019-06-24 | 2019-11-15 | 深圳市汇顶科技股份有限公司 | Project structured light device, project structured light method and three-dimension measuring system |
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